class_docstr: Scales data in range -pi/2 to pi/2 (-90 to 90 degrees) using
  the system used to scale latitudes in a Mercator__ projection.
  
  The scale function:
    ln(tan(y) + sec(y))
  
  The inverse scale function:
    atan(sinh(y))
  
  Since the Mercator scale tends to infinity at +/- 90 degrees,
  there is user-defined threshold, above and below which nothing
  will be plotted.  This defaults to +/- 85 degrees.
  
  __ https://en.wikipedia.org/wiki/Mercator_projection
docstr: Any keyword arguments passed to ``set_xscale`` and ``set_yscale`` will
  be passed along to the scale's constructor.
  
  thresh: The degree above which to crop the data.
docstr_tok: ["Any","keyword","arguments","passed","to","``","set_xscale","``","and","``","set_yscale","``","will","be","passed","along","to","the","scale","'s","constructor",".","thresh",":","The","degree","above","which","to","crop","the","data","."]
code: def __init__(self, axis, *, thresh=np.deg2rad(85), **kwargs):
      """
      Any keyword arguments passed to ``set_xscale`` and ``set_yscale`` will
      be passed along to the scale's constructor.
  
      thresh: The degree above which to crop the data.
      """
      super().__init__(axis)
      if thresh >= np.pi / 2:
          raise ValueError("thresh must be less than pi/2")
      self.thresh = thresh
  
file_path: matplotlib/galleries/examples/scales/custom_scale.py
imports: import numpy
  from numpy import ma
  from matplotlib import scale
  from matplotlib import transforms
  from matplotlib.ticker import FixedLocator, FuncFormatter
label_desc: Use image node_id 1 to create a new MercatorLatitudeScale object from inherited base classes: mscale with example: obj = MercatorLatitudeScale(axis)